1. Field of the Invention
This application relates to an inexpensive shield incorporated into a lamp assembly. More particularly, this invention relates to a high intensity discharge reflector lamp assembly, such as used in projector equipment, but need not necessarily be limited to this end use.
2. Discussion of the Art
Projector equipment often employs a high intensity discharge light source. Generally, the discharge light source operates at a high temperature/high pressure whereby the pressurized gas fill sealed in a light transmissive envelope is converted into a light emitting discharge plasma. Efficacy of the lamp assembly is directly related to the operating pressure and temperature of the lamp. It thus becomes important to operate at a high temperature without adversely impacting the surrounding environment.
It is important, therefore, to provide thermal venting for the lamp. In some instances this must be attained without impacting on the light emitting properties of the lamp assembly. That is, the light source is housed within a surrounding reflector body. The reflector body is positioned around the lamp to redirect light from the source through an open end or cover/lens that seals one end of the reflector body. An opposite end of the reflector body includes a reduced diameter neck or opening through which the electrodes of the discharge light source extend.
It is conventional with lamp assemblies of this type for the reflector body to be reinforced or employ a separate containment shield to contain a nonpassive failure of the light source. Unfortunately, the containment structure further impedes heat transfer and adds to an increased operating temperature, and thus reduced operating life, of the lamp.
Although alternative cooling structures have been suggested, they have been unnecessarily complex or expensive because of the need to machine the reflector to accommodate cooling features or provide a complex reflector assembly. For example, openings must be formed in the reflector body to allow air flow from the cooling fan to reach the interior cavity of the reflector body and thus reduce the operating temperature of the light source.
Accordingly, a need exists for a simple, yet effective solution to a containment structure that provides thermal venting for the lamp assembly.
An improved lamp assembly includes a perforated or foraminous containment structure that provides effective thermal venting.
In a first embodiment, the assembly includes discrete perforated panel portions positioned over reflector body vent openings. The panel portions are disposed in spaced relation about the reflector body so as not to contribute to heat containment within the lamp assembly.
In one embodiment, the panel portions are interconnected by a structural member, namely a support wire, that freely supports and positions the vent panel portions relative to the reflector body.
In another preferred embodiment, an open ended sleeve is received in the reflector body and the sleeve is perforated along its length.
In another preferred embodiment, the panel portions are adhesively secured to the reflector body.
Yet another preferred embodiment interconnects the panel portions and adhesively secures the assembly to the reflector body.